As the complexity of integrated circuits increases, so may the number of functions provided by the integrated circuits. The function provided by the integrated circuit may be selected and a label placed on the package of the integrated circuit to identify the function provided by the integrated circuit.
The function of the integrated circuit may later be identified by applying a voltage to the integrated circuit and observing the resulting current. U.S. Pat. No. 5,103,166 to Jeon et al. discusses identification circuitry including a voltage limiter which limits an input potential difference between a power supply terminal and an input terminal to a predetermined voltage. U.S. Pat. No. 4,480,199 to Varshney et al. discusses an identification circuit wherein, a single identification circuit may be electrically connected to a pad of the integrated circuit. As described above, a voltage may be applied to the pad, causing a current to flow which may be used to identify the function provided by the integrated circuit. As the number of functions provided by the integrated circuit increases, however, so may the number of required pads also increase, which may increase the cost and/or complexity of the integrated circuit. In view of the above, there continues to exist a need to further improve the identification of functions provided by integrated circuits.